A major structural component of a commonly configured air impingement conveyor oven comprises a thermally insulated box type baking case having an upper wall or ceiling, a lower wall or floor, a lateral or side wall, an oppositely lateral or opposite side wall, a longitudinal or end wall, and an oppositely longitudinal or opposite end wall. Such baking case's longitudinal and oppositely longitudinal walls typically include laterally oblongated food passage ports through which a cooking rack type continuous loop food conveyor longitudinally extends. In operation of such typically configured air impingement food conveyor, food items such as pizzas may be placed upon the conveyor at its longitudinal end. The food items are then carried by the conveyor into the baking case through the food passage port within the baking case's longitudinal wall, and are further carried across the interior of the baking case. The food items are then carried out of the baking case through the food passage port within the baking case's oppositely longitudinal wall. In order to preserve the heating and cooking efficiency of such conveyor ovens, the opening sizes of the food passage ports are typically minimized (consistent with providing clearance for the size of food items to be cooked), and other structures such as apertures, ports, conduits, gapped seams and joints, and the like which may further open the baking case to the outside room environment are typically eliminated.
A further structural component of such typically configured air impingement conveyor ovens comprises an air intake manifold or air plenum mounted within the baking case between the baking case's lateral or back wall and the lateral side of the food conveyor. Such air plenum typically has one or more air intake ports opening the plenum's lateral wall, and such air plenum typically has a plurality of air duct outlets or ports which open the plenum's oppositely lateral wall. A plurality of air impingement “finger” ducts are also typically provided, a proximal end of each such duct communicating with one of the air plenum's air duct outlets. Such finger ducts typically extend oppositely laterally from the air plenum to positions overlying and/or underlying the food conveyor. Such finger ducts also typically include registers configured and positioned to direct jets of impingement air downwardly and/or upwardly toward the food conveyor and against the food items carried thereon. Typically, a blower or fan is operatively mounted at the air plenum's air intake port for drawing air from the air volume at the lateral side of the air plenum into the air plenum, and for driving such air oppositely laterally through the air ducts outlets for forced air impingement cooking of the food items carried on the conveyor.
The combined action and operation of the above described air blower, air plenum, and finger ducts assembly within such typically configured air impingement conveyor oven tends to create turbulence and a significant air pressure differential between the laterally divided portions of the baking case's interior space. In such ovens, a low pressure air volume is created by such assembly at the lateral side of the air plenum, and a corresponding high pressure air volume is created at the oppositely lateral side of the air plenum. As a result of such air turbulence and air volume air pressure differential, the desirable hermetic character of the walls of the baking case, as discussed above, has enhanced importance. Conduits, ports, or apertures which are allowed to open a wall of the baking case at the case's oppositely lateral high pressure side are generally known to emit heated air from the baking case, and to thereby undesirably lower the cooking efficiency of the oven. Likewise, conduits, ports, or apertures which are allowed to open the baking case at the case's low pressure lateral side tend to undesirably aspirate cool outside air into the baking case, similarly diminishing the cooking efficiency of the oven. The longitudinally positioned food passage ports discussed above constitute a necessary exception to the known and conventionally understood baking case design criteria requiring that the walls of the baking case be hermetic and imperforate.
As a result of such air pressure differences and turbulence generated by such baking case mounted blower, air plenum, and finger duct assemblies, oven designers and fabricators have traditionally been motivated to maximize the hermetic and imperforate character of all of the walls of the oven's case. In contrast with and counter to such traditional design motivation, the instant invention provides at least a first, and preferably first and second open air flow conduits (in addition to the requisite longitudinal wall opening food passage ports discussed above), each open air flow conduit extending through one of the baking case's walls. Yet, the instant invention inter-positions such open air flow conduits and associates burner components in a manner which counters the commonly understood undesirability of extending open conduits through oven walls, and in a manner which enhances rather than diminishes the overall efficiency of the oven.